QRectF rect(0, 1 * m_tracksHeight + m_tracksHeight / 2, sceneRect().width(), 2);
QList<QGraphicsItem *> selection = m_scene->items(rect);
QStringList timelineList;
QRectF rect(0, 1 * m_tracksHeight + m_tracksHeight / 2, sceneRect().width(), 2);
QList<QGraphicsItem *> selection = m_scene->items(rect);
QStringList timelineList;